Chladni plates, harmonics and geometry
If you never have heard of Chladni plates and patters, check out the following two links and the subject: Chladni plates and Chladni patterns for a violin. The last link provides some insight on the matter, whereas the first only shows you some intriguing pictures.
The patterns are related to the eigenmodes of the geometry an each corresponds to a harmonic function over the geomtry at hand. The relation of these pattern to the properties of the geometry makes them an important tool to scientists that want computer algorithms to ‘understand’ geometry. Though awareness and experimentation is on the rise, we are far from a full understanding how to use these magical patterns to their full potential.